Weeknight’s shadowy debut, Post-Everything, comes on like the mascara-smeared work of some Bela Lugosi-worshipping Goth kids. In a recent phone interview, however, singer/guitarist Andy Simmons, who cofounded the band in 2011 with his girlfriend of nearly a decade Holly MacGibbon, projected a relatively happy-go-lucky demeanor, even confessing to a secret obsession with the Zooey Deschanel comedy series “The New Girl.”

“Well I guess it’s not so secret anymore,” he said, and laughed. “But I like funny things, and I like to laugh.”

It shouldn’t surprise then that the couple actually stumbled onto its creep-inducing, synth-pop sound almost entirely by accident. When the two musicians first started writing together, they toyed with all types of sounds and song structures, dabbling in everything from electro-pop to synth-smeared folk.

“When we began working on these songs we were experimenting a lot,” Simmons said. “I’ve gone through some of our old sessions and it’ll be like, ‘What is that? I don’t even recognize that song anymore.’”

A key element of the group’s sound — those whispered, cobwebby vocal harmonies — actually evolved in large part because of the substandard equipment the musicians had on hand.

“I had a really bad microphone, and it just sounded terrible,” Simmons said. “So we cranked the reverb [on the vocals] and it was like, ‘You know, that’s kind of cool.’”

The harmonies are further rooted in the religious hymns Simmons absorbed as a child. His grandmother was a longtime church organist, and his earliest musical memories involve listening to her play for the congregation. Even so, the guitarist resisted the urge to pick up an instrument until he heard Nirvana as a 10-year-old and subsequently formed a band with friends. Though uncomfortable in the spotlight, he was thrust into the role as frontman because, in his own words, “I was the only dude who could get my scream close enough to Kurt Cobain.”

Nowadays Simmons is slightly more comfortable center stage — “Discovering booze helped,” he said — though his screams have been muffled and replaced by Weeknight’s far-more-disquieting harmonies, which are often employed in service to some fairly bleak tales. Take “Dark Light,” for one, a moody, electro-tinged burner where two lovers huddle close in anticipation of the end. Here’s hoping the doomed couple at least had a chance to catch the latest “New Girl” before the final curtain fell.